Halogen-free flame-retardant PEF / PC alloy material as well as preparation method and application thereof

Abstract

The invention discloses a halogen-free flame-retardant PEF / PC alloy material as well as a preparation method and application thereof. The halogen-free flame-retardant PEF / PC alloy material comprises the following components: PEF resin, PC resin, a halogen-free flame retardant, a compound synergist and an auxiliary agent, wherein the PC resin comprises PC resin containing an organosilicon group. The flame retardant property and heat resistance of the material can be remarkably improved by compounding the silicon PC and the PFF, the compound synergist uniformly dispersed in the material forms nano-scale reinforcing points and cooperates with the silicon PC for flame retardance, so that the mechanical property and flame retardant effect of the material are further improved, and the finally obtained composite material is relatively good in flame retardant property and mechanical property, and is suitable for industrial production. The invention is suitable for household appliances.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a halogen-free flame-retardant PEF / PC alloy material, its preparation method, and its application. Background Technology

[0002] Polyethylene 2,5-furandicarboxylate (PEF), as a bio-based polyester, possesses unique advantages, including 100% bio-based composition, recyclability, and biodegradability, making it a promising material for numerous applications. As products move towards higher-end products, higher demands are being placed on the flame-retardant properties of materials. The European electronics market is gradually raising its standards for flame-retardant materials; for example, Australia's standards, implemented on October 30, 2010, require non-metallic materials to pass an 850°C glow wire test. To meet these stringent requirements, enhancing the flame-retardant properties of PEF has become crucial. While traditional bromine-antimony flame retardant systems offer high flame-retardant performance and good mechanical properties, their CTI (tracking index) and GWIT (glow wire ignition temperature) are often low. Generally, halogen-free flame-retardant PEF materials have a CTI below 225V and a GWIT not exceeding 750°C. This limits their application in fields with high flame-retardant requirements. On the other hand, while using a halogen-free flame-retardant system can enable PEF materials to achieve a GWIT of 850°C and a CTI of over 500V, meeting high flame-retardant standards, the amount of halogen-free flame retardant added is usually higher, resulting in a significant loss of mechanical properties compared to the traditional bromine-antimony system. This decline in mechanical properties is particularly detrimental to the manufacture of thin-walled electronic components used in unattended white goods, easily leading to product cracking and thus limiting the application of halogen-free flame-retardant PEF systems in these fields.

[0003] Therefore, how to improve the flame retardant properties of PEF while maintaining its excellent mechanical properties has become an urgent problem to be solved in current PEF material research. Summary of the Invention

[0004] The main objective of this invention is to provide a halogen-free flame-retardant PEF / PC alloy material, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] One aspect of the present invention provides a halogen-free flame-retardant PEF / PC alloy material comprising the following components: PEF resin, PC resin, halogen-free flame retardant, compounding synergist, and additives; wherein the PC resin comprises PC resin containing organosilicon groups.

[0007] Another aspect of the present invention provides a method for preparing the aforementioned halogen-free flame-retardant PEF / PC alloy material, comprising: melting and blending the PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives to form a mixed system; extruding and granulating the mixed system to obtain the halogen-free flame-retardant PEF / PC alloy material.

[0008] Another aspect of the present invention provides the application of the aforementioned halogen-free flame-retardant PEF / PC alloy material in the field of home appliances.

[0009] Compared with the prior art, the present invention has at least the following advantages:

[0010] The halogen-free flame-retardant PEF / PC alloy material provided by this invention can significantly improve flame retardancy and heat resistance by combining silicon PC with PFF. The use of compound synergists can significantly improve the dispersibility and flowability of the composition. The compound synergists are uniformly dispersed in the material to form nanoscale reinforcing points, which synergistically enhance flame retardancy with silicon PC, further improving the mechanical properties and flame retardant effect of the material. The final composite material has good flame retardant and mechanical properties, and is suitable for thin-walled electronic components in the home appliance field. Detailed Implementation

[0011] The invention will be more fully understood by reading the following detailed description. However, it should be understood that the detailed description disclosed below is merely exemplary of the invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention in different ways in any suitable detailed embodiment.

[0012] As one aspect of the technical solution of the present invention, a halogen-free flame-retardant PEF / PC alloy material includes the following components: PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives; wherein, the PC resin includes PC resin containing organosilicon groups.

[0013] In some embodiments, the halogen-free flame-retardant PEF / PC alloy material comprises the following components by weight percentage: 47-77% PEF resin, 5-20% PC resin, 8-15% halogen-free flame retardant, 1-16% compound synergist, and 0.1-7% additives.

[0014] Regarding the matrix resin material mentioned above, PEF, or polyethylene 2,5-furandicarboxylate, is a bio-based polyester. It can be synthesized using FDCA as a monomer by adding ethylene glycol via direct esterification or transesterification.

[0015] As a preferred example, the PEF resin selected in this invention has an intrinsic viscosity of 0.8 or even lower, which is different from the conventional PEF with an intrinsic viscosity of 1.0. The low viscosity PEF resin has better flowability and is more suitable for injection molding thin-walled products. When made into PEF / PC alloy material with PC resin, it has higher flowability.

[0016] The PC described in this invention is a silicon PC material. The addition of silicon PC significantly improves the flame retardant properties and heat resistance of PEF, resulting in a final composition with a higher flame retardant rating and better thermal stability.

[0017] In some embodiments, the PC resin includes, but is not limited to, PC resins containing organosilicon groups.

[0018] As a typical example, the silicone PC resin of this invention employs a block copolymer of polydimethylsiloxane-containing silicone PC. This copolymerized silicone PC, by introducing organosilicon groups, significantly improves its flexibility, hydrolysis resistance, corrosion resistance, oxidation resistance, and yellowing resistance. Compared to traditional polycarbonate PC, the copolymerized silicone PC exhibits increased structural unit length, reduced rigidity of the large benzene ring, and enhanced flexibility of the molecular chain, thereby achieving a significant improvement in material properties. This improvement not only enhances the flowability of the PC material but also endows it with higher heat resistance and yellowing resistance. Due to the unique structure of organosilicon introduced into the copolymerized silicone PC, this material is particularly suitable for injection molding large-sized, thin-walled electronic and electrical products. Furthermore, the PEF / PC alloy material formed with PEF exhibits better flowability, heat resistance, and processing performance, further broadening its application range.

[0019] More specifically, the silicon copolymer polycarbonate includes, but is not limited to, any one or a combination of two or more of the PCs with the grades ST4-3022, 8000-05, ST6-3022PJ, and EXL1414T.

[0020] In some implementations, the halogen-free flame retardant includes, but is not limited to, organic flame retardants.

[0021] In some preferred embodiments, the halogen-free flame retardant includes, but is not limited to, phosphate ester flame retardants.

[0022] In some more preferred embodiments, the phosphate ester flame retardant includes, but is not limited to, any one or a combination of two or more of phenoxy polyphosphazene, PX-200, and PX-220.

[0023] The halogen-free flame retardant of this invention can be made of phenoxy polyphosphazene, which has higher fluidity, high temperature resistance, and UV resistance compared to ordinary halogen-free flame retardants. Ordinary organic halogen-free flame retardants have low thermal stability and low flame retardant efficiency, while this high-temperature resistant halogen-free flame retardant has excellent thermal stability, with a TGA thermal decomposition temperature >380℃.

[0024] In some implementations, the compound synergist includes, but is not limited to, inorganic flame retardants.

[0025] In some preferred embodiments, the compound synergist includes, but is not limited to, any one or a combination of two or more of nano-silica, nano-montmorillonite, and nano-zinc oxide.

[0026] The compound synergist of the present invention can be nano-silica. Compared with ordinary synergists, its high heat resistance ensures the stability of the flame retardant during the screw extrusion process. It can greatly reduce the degradation of the flame retardant caused by the internal heat generated by the thermal shear during the extrusion process, thereby reducing the loss of the flame retardant, improving the effective utilization rate of the flame retardant, and enabling the material to maintain good flame retardant and mechanical properties.

[0027] In some embodiments, the additives include, but are not limited to, any one or a combination of two or more of transesterification inhibitors, compatibilizers, antioxidants, and lubricants.

[0028] In some embodiments, the halogen-free flame-retardant PEF / PC alloy material comprises the following components by weight percentage: 47-77% PEF resin, 5-20% PC resin, 8-15% halogen-free flame retardant, 1-16% compounding synergist, 0.2-0.5% transesterification inhibitor, 1-5% compatibilizer, 0.1-0.4% antioxidant, and 0.1-0.5% lubricant.

[0029] Of course, the above-mentioned range of mass fractions is within the preferred range involved in the long-term experiments of the inventors in this case, and does not mean a strict limitation of the feasible range. For example, the content of resin may exceed the above range to a certain extent, or the content of other selected additives may be appropriately adjusted, or even the selected additives may be introduced or deleted, all of which are within the scope of implementation of the basic technical concept of this invention.

[0030] Furthermore, regarding the selected additives mentioned above, in some preferred embodiments, the transesterification inhibitors include, but are not limited to, alkyl phosphate transesterification inhibitors, which can effectively prevent transesterification reactions from occurring in polyester alloys.

[0031] As some typical examples, the transesterification inhibitors include, but are not limited to, any one or a combination of two or more of the transesterification inhibitors with the commercial brands AX-71, PGP-B, and PS-820.

[0032] In some embodiments, the compatibilizer includes, but is not limited to, a random terpolymer of ethylene, acrylate, and glycidyl methacrylate (GMA) with a grafting rate of up to 8% or higher; the acrylate provides flexibility and polarity while maintaining high thermal stability during processing. High acrylate content results in high flexibility (low crystallinity) and high impact absorption performance. More specifically, the compatibilizer includes, but is not limited to, any one or a combination of two or more of the commercially available compatibilizers AX8900, PTW, and SOG-02, which, upon addition, enable excellent compatibility between PEF and PC and improve the impact strength of the PEF / PC alloy material.

[0033] In some embodiments, the antioxidant includes, but is not limited to, asymmetric hindered phenolic antioxidants.

[0034] As some typical examples, the antioxidant is an asymmetric hindered phenolic antioxidant. Preferably, the asymmetric hindered phenolic antioxidant includes at least one of the commercially available antioxidants with the brand names AO-80 and S80, but is not limited to this. Asymmetric hindered phenolic antioxidants have the characteristics of good compatibility, low volatility, good thermal stability, and high antioxidant efficiency. They prevent extraction and migration losses and inhibit nitrogen oxide coloring. Compared with symmetric hindered phenolic antioxidants, they can solve problems such as yellowing, degradation, and deterioration of physical properties caused by degradation during high-temperature processing and long-term high-temperature use.

[0035] In some embodiments, the lubricant includes, but is not limited to, pentaerythritol stearate. This lubricant exhibits excellent thermal stability and low volatility, maintaining stable performance under various high-temperature environments. Furthermore, it possesses good release and flow properties, making the processing smoother, and has a heat resistance temperature exceeding 350 degrees Celsius. Preferably, pentaerythritol stearate includes, but is not limited to, any one or a combination of two or more lubricants with commercial brand names SL-440AT, PT100, and EW-480T.

[0036] As another aspect of the technical solution of the present invention, the preparation method of the aforementioned halogen-free flame-retardant PEF / PC alloy material includes: melting and blending the PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives to form a mixed system; extruding and granulating the mixed system to obtain the halogen-free flame-retardant PEF / PC alloy material.

[0037] In some embodiments, the preparation method specifically includes: adding the PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives into the feed hopper of an extruder, entering a co-rotating parallel twin-screw extruder for melt blending, extruding by the co-rotating parallel twin-screw extruder, cooling in a water tank and then cutting into granular particles by a pelletizer to obtain the halogen-free flame retardant PEF / PC alloy material.

[0038] In some preferred embodiments, the co-rotating parallel twin-screw extruder has a rotational speed of 250-300 RPM, a current of 30-45 A, and an extrusion temperature of 210-250 °C.

[0039] As a typical specific example of the above-mentioned overall technical solution, the preparation method described above can be described as follows:

[0040] 1) Weigh each raw material according to the proportions;

[0041] 2) Mix PEF, PC, halogen-free flame retardant, compound synergist, compatibilizer, transesterification inhibitor, antioxidant and lubricant in proportion and stir evenly. After melt blending, a mixed system is formed.

[0042] 3) The mixed system is extruded and granulated to obtain halogen-free flame-retardant PEF / PC alloy material.

[0043] Specifically, the above raw materials are premixed in a high-speed mixer for 3-5 minutes to ensure thorough mixing. The mixture is then fed into a co-rotating parallel twin-screw extruder for melt blending, extruded, cooled in a water bath, and then cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material.

[0044] Regarding the preparation process conditions, the reference values ​​for the rotational speed of the co-rotating parallel twin-screw extruder are 280 RPM, the current is 30-45 A, and the extrusion temperature is 210-250℃. Of course, the specific process conditions can be adjusted appropriately, and those skilled in the art are capable of conducting condition experiments to find optimal process conditions.

[0045] As another aspect of the technical solution of the present invention, it also relates to the application of the aforementioned halogen-free flame-retardant PEF / PC alloy material in the field of home appliances, especially in the preparation of thin-walled shells for white home appliances.

[0046] This invention uses PEF resin with good flowability as the main base material, and adds silicone copolymer PC resin with high temperature resistance and excellent oxidation resistance to form a high-performance alloy material. Based on this, the inventors carefully selected high-temperature resistant halogen-free flame retardants and flame retardant synergists, and synergistically formulated them with other key components to optimize overall performance. Through this innovative approach, the prepared halogen-free flame-retardant PEF / PC alloy material exhibits superior electrical properties, including a high CTI (comparative tracking index) and GWIT (glow wire ignition temperature). Simultaneously, the material also possesses excellent flame-retardant properties, effectively resisting the spread of fire.

[0047] Compared with traditional halogen-free flame-retardant PEF, the alloy material prepared by this invention exhibits significant advantages in several aspects. The addition of silicon PC significantly improves the flame-retardant properties and heat resistance of PEF, resulting in a final composition with a higher flame-retardant rating and better thermal stability. The addition of synergists, which are uniformly dispersed in the material, forms nanoscale reinforcing points, further improving the material's mechanical properties and flame-retardant effect. In addition, the synergists also improve the surface properties of the material, making it easier to shape and surface treat during processing.

[0048] Specifically, based on the above technical solution, the halogen-free flame-retardant PEF / PC alloy material provided in this invention exhibits superior comprehensive performance. In some preferred embodiments, its tracking resistance index can reach 400V, its glow wire ignition temperature (GWIT) can reach 850℃ / 1.0mm, its UL94 flame retardancy rating reaches 0.8mmV0, its tensile strength exceeds 60MPa, its flexural strength exceeds 100MPa, and its notched impact strength reaches 20KJ / m. 2 above.

[0049] The present invention is further illustrated below by way of examples, but the invention is not limited to the scope of the examples described. All reagents and raw materials used in the following examples are commercially available, and test methods not specifically specified are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0050] Example 1

[0051] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 67% PEF resin, 8% copolysilicon PC ST6 resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 12% compound synergist nano-silica, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0052] (1) Weigh out each raw material according to the proportion;

[0053] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0054] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 39 A, and the extrusion temperature is 230℃.

[0055] Example 2

[0056] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 63% PEF resin, 12% copolysilicon PC ST6 resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 12% compound synergist nano-silica, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0057] (1) Weigh out each raw material according to the proportion;

[0058] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0059] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0060] Example 3

[0061] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 59% PEF resin, 12% copolysilicon PC ST6 resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 16% compound synergist nano-silica, 0.2% antioxidant AO-800, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0062] (1) Weigh out each raw material according to the proportion;

[0063] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0064] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0065] Example 4

[0066] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 57% PEF resin, 16% copolysilicon PC ST6 resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 8% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 16% compound synergist nano zinc oxide, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0067] (1) Weigh out each raw material according to the proportion;

[0068] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0069] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 41 A, and the extrusion temperature is 230℃.

[0070] Example 5

[0071] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 47% PEF resin, 20% copolysilicon PC ST6 resin, 0.4% transesterification inhibitor AX-71, 1% compatibilizer AX8900, 15% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 15.7% compound synergist nano-silica, 0.4% antioxidant AO-80, and 0.5% lubricant EW-480T, and is prepared by the following steps:

[0072] (1) Weigh out each raw material according to the proportion;

[0073] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0074] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The co-rotating parallel twin-screw extruder has a rotation speed of 250 RPM, a current of 35 A, and an extrusion temperature of 210 °C.

[0075] Example 6

[0076] This invention provides a halogen-free flame-retardant PEF / PC alloy material, comprising the following raw materials by mass percentage: 77% PEF resin, 5% copolysilicon PC ST6 resin, 0.2% ester exchange inhibitor AX-71, 5% compatibilizer AX8900, 11.6% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 1% compound synergist nano-silica, 0.1% antioxidant AO-800, and 0.1% lubricant EW-480T, and is prepared by the following steps:

[0077] (1) Weigh out each raw material according to the proportion;

[0078] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0079] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain halogen-free flame-retardant PEF / PC alloy material. The co-rotating parallel twin-screw extruder has a rotation speed of 300 RPM, a current of 45 A, and an extrusion temperature of 250 °C.

[0080] Comparative Example 1

[0081] The present invention provides a PEF / PC alloy material, comprising the following raw materials by mass percentage: 63% PEF resin, 12% copolysilicon PC ST6 resin, 0.5% transesterification inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 12% compounding synergist nano-silica, 0.2% antioxidant 1098, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0082] (1) Weigh out each raw material according to the proportion;

[0083] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0084] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0085] Comparative Example 2

[0086] The present invention provides a PEF / PC alloy material, comprising the following raw materials by mass percentage: 63% PEF resin, 12% conventional PC 2200R resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 12% compounding synergist nano-silica, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0087] (1) Weigh out each raw material according to the proportion;

[0088] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0089] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0090] Comparative Example 3

[0091] The present invention provides a PEF / PC alloy material, comprising the following raw materials by mass percentage: 78% PEF resin, 5% copolysilicon PC resin, 0.5% ester exchange inhibitor AX-71, 2% compatibilizer AX8900, 10% high-temperature halogen-free flame retardant phenoxy polyphosphazene, 4% compounding synergist nano-silica, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0092] (1) Weigh out each raw material according to the proportion;

[0093] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0094] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0095] Comparative Example 4

[0096] The present invention provides a PEF / PC alloy material, comprising the following raw materials by mass percentage: 63% PEF resin, 12% copolysilicon PC ST6 resin, 0.5% transesterification inhibitor AX-71, 2% compatibilizer AX8900, 10% common halogen-free flame retardant PX-220, 12% compound synergist nano-silica, 0.2% antioxidant AO-80, and 0.3% lubricant EW-480T, and is prepared by the following steps:

[0097] (1) Weigh out each raw material according to the proportion;

[0098] (2) Put the raw materials into a high-speed mixer with a speed of 300 RPM and mix for 5 minutes until they are evenly mixed to form a mixture;

[0099] (3) The mixture is added to the feed hopper of the extruder and fed into the co-rotating parallel twin-screw extruder for melt blending and extrusion. After cooling in a water tank, it is cut into granules by a pelletizer to obtain PEF / PC alloy material. The rotation speed of the co-rotating parallel twin-screw extruder is 280 RPM, the current is 40 A, and the extrusion temperature is 230 °C.

[0100] The formulations of Examples 1-4 and Comparative Examples 1-4 are shown in Table 1:

[0101] Table 1:

[0102]

[0103] Performance tests were conducted on the above embodiments and comparative examples, and the results are shown in Table 2:

[0104] Table 2:

[0105]

[0106] As can be seen from Tables 1 and 2, the test results of Example 2 and Comparative Example 1 show that replacing the symmetric antioxidant 1098 with the asymmetric antioxidant AO-80 can improve the tensile strength, flexural strength and other properties of the material.

[0107] As can be seen from Tables 1 and 2, the test results of Example 2 and Comparative Example 2 show that after replacing conventional PC 2200R with copolysilicon PC ST6 resin, the GWIT is higher, the flame retardant performance is better, and the mechanical properties are also increased to a certain extent. This indicates that the electrical properties, flame retardancy, flowability and temperature resistance of copolysilicon PC resin are better than those of conventional PC resin, which can improve the comprehensive performance of alloy materials.

[0108] As can be seen from the test results of Example 2 and Comparative Example 3 in Tables 1 and 2, when the proportion of PEF is excessive, its bending strength, notched impact strength of simply supported beam, and ignition temperature of glow wire all decrease.

[0109] As can be seen from Tables 1 and 2, the test results of Example 2 and Comparative Example 4 show that after replacing the conventional halogen-free flame retardant PX-220 with the high-temperature resistant halogen-free flame retardant phenoxy polyphosphazene, the comprehensive mechanical properties and heat resistance of the alloy material are improved. This indicates that phenoxy polyphosphazene has better temperature resistance and is less prone to degradation due to screw thermal shear during extrusion granulation, thus minimizing the thermal decomposition of the material and maintaining its high mechanical properties.

[0110] As can be seen from Tables 1 and 2, the test results of Examples 2 and 3 show that increasing the content of the compound synergist nano-silica in the halogen-free flame-retardant PEF / PC alloy system significantly improves the CTI value, flame retardancy, and GWIT performance of the material, while slightly reducing the mechanical properties. The increase of the compound synergist is beneficial to improving the CTI and GWIT of the material.

[0111] The halogen-free flame-retardant PEF / PC alloy material provided in this embodiment of the invention uses low-viscosity, high-flowability PEF resin and adds silicon copolymer PC resin with high temperature resistance and good oxidation resistance to form an alloy material. A high-temperature resistant halogen-free flame retardant is selected and combined with other components in a synergistic ratio to make the prepared halogen-free flame-retardant PEF / PC alloy material have a high CTI (450V), a high GWIT (875℃ / 1.0mm), and excellent flame-retardant properties, and the flame retardant rating can reach 0.8mmV0.

[0112] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0113] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A halogen-free flame-retardant PEF / PC alloy material, characterized in that, It comprises the following components: PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives; wherein the PC resin includes PC resin containing organosilicon groups.

2. The halogen-free flame-retardant PEF / PC alloy material according to claim 1, characterized in that, It includes the following components by weight percentage: 47-77% PEF resin, 5-20% PC resin, 8-15% halogen-free flame retardant, 1-16% compound synergist, and 0.1-7% additives.

3. The halogen-free flame-retardant PEF / PC alloy material according to claim 1, characterized in that, The PC resin includes a silicone-containing PC resin copolymerized with polydimethylsiloxane block copolymer; And / or, the halogen-free flame retardant includes an organic flame retardant with a thermal decomposition temperature higher than 380°C; preferably, the organic flame retardant includes any one or a combination of two or more of phenoxy polyphosphazene, PX-200, and PX-220. And / or, the compound synergist includes an inorganic flame retardant with a thermal decomposition temperature higher than 350°C; preferably, the inorganic flame retardant includes any one or a combination of two or more of nano-silica, nano-montmorillonite, and nano-zinc oxide.

4. The halogen-free flame-retardant PEF / PC alloy material according to claim 1, characterized in that, The additives include any one or a combination of two or more of the following: transesterification inhibitors, compatibilizers, antioxidants, and lubricants.

5. The halogen-free flame-retardant PEF / PC alloy material according to claim 4, characterized in that, It includes the following components by weight percentage: 47-77% PEF resin, 5-20% PC resin, 8-15% halogen-free flame retardant, 1-16% compound synergist, 0.2-0.5% transesterification inhibitor, 1-5% compatibilizer, 0.1-0.4% antioxidant, and 0.1-0.5% lubricant.

6. The halogen-free flame-retardant PEF / PC alloy material according to claim 4, characterized in that, The transesterification inhibitor includes alkyl phosphate transesterification inhibitors; preferably, the alkyl phosphate transesterification inhibitor includes any one or a combination of two or more of AX-71, PGP-B, and PS-820. And / or, the compatibilizer comprises a random terpolymer of ethylene, acrylate and glycidyl methacrylate, with a grafting rate of 8% or higher.

7. The halogen-free flame-retardant PEF / PC alloy material according to claim 4, characterized in that, The antioxidant includes asymmetric hindered phenolic antioxidants; preferably, the asymmetric hindered phenolic antioxidants include any one or a combination of two of AO-80 and S80. And / or, the lubricant comprises a stearate polymer; preferably, the stearate polymer comprises any one or a combination of two or more of SL-440AT, PT100, and EW-480T.

8. A method for preparing the halogen-free flame-retardant PEF / PC alloy material according to any one of claims 1-7, characterized in that, include: The PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives are melt-blended to form a mixed system; The mixture is extruded and granulated to obtain the halogen-free flame-retardant PEF / PC alloy material.

9. The preparation method according to claim 8, characterized in that, Specifically, it includes: The PEF resin, PC resin, halogen-free flame retardant, compound synergist and additives are added to the feed hopper of an extruder and fed into a co-rotating parallel twin-screw extruder for melt blending. The mixture is then extruded by the co-rotating parallel twin-screw extruder, cooled in a water tank, and then cut into granules by a pelletizer to obtain the halogen-free flame retardant PEF / PC alloy material. Preferably, the co-rotating parallel twin-screw extruder has a rotational speed of 250-300 RPM, a current of 30-45 A, and an extrusion temperature of 210-250 °C.

10. The application of the halogen-free flame-retardant PEF / PC alloy material according to any one of claims 1-7 in the field of household appliances; Preferably, the application includes: The halogen-free flame-retardant PEF / PC alloy material is used to prepare electrical appliance housings.

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